What is your battery voltage right after unplugging

[georgeaz]

I have a 2017 LADP. I am curious to know what others see for voltage right after unplugging. I ask because 5 mins after unplugging the generator kicked on for a chassis charge via the Silver Leaf system. I have been complaining to Newmar for awhile that the chassis batteries are not good. They said it passed a load test a few months back. Not really buying it.

When I unplug I have 12.8v for the house batteries (solar package with AGMs). And I have 12.6v for the chassis batteries. This is right after unplugging.

This seems low to me. Is this normal?

Thanks your your help!

G

[vsheetz]

The battery voltages seem as expected. SoC table below - which is without load.

At what voltage is your AGS set to start?

[georgeaz]

This is a great chart. Thank you.

I have to look at the settings again but I think 12.4 for chassis start and 12.2 for house batteries.

G

[Starmaster]

The voltages seem reasonable for after 5 minutes from unplugging.

Just a thought, is there a SilverLeaf setting that determines when the gen needs to start based on battery voltage? Maybe that is set too high?

I know the Magnum AGS option is settable. The batteries don’t really need a charge until 12.0vdc (~50% discharged).

Any SilverLeaf experts out there?

Dave

[vsheetz]

Settings for AGS, if too high cause nusence starting - and if too low, no start. And short term loads will dip battery voltage... Causing unwanted starts.

Moving out of band via a separate starting battery for the generator resolves many complications.

I don't use AGS. Instead just managing battery voltage myself.

[Rd1]

silverleaf AGS setting of 12.0v is sufficient for both batts. and if you have sufficient solar watts, they should maintain the batts, when there is avg battery usage. I have 950 W of solar and the ags hardly ever kicks in to charge the batts, during most of the year.

[Pogo]

The voltage reading on a nearly discharged battery could read the same as on a fully charged one, until a load is applied. Then you can tell the difference. You can google this and find explanations for it, and the experts here could explain it too. (kind of like a water pump pressure with no water flowing vs water flowing)
So, just reading voltage on a battery at rest, can possibly be misleading.
Hopefully, this will help.

[twinboat]

Originally Posted by Pogo

The voltage reading on a nearly discharged battery could read the same as on a fully charged one, until a load is applied.
So, just reading voltage on a battery at rest, can possibly be misleading.
Hopefully, this will help.

That is not true.

From Trojan Battery

. Open-Circuit Voltage Test
For accurate voltage readings, batteries must remain idle (no charging, no discharging) for at least 6 hrs, preferably 24 hrs.

Disconnect all loads from the batteries.

Measure the voltage using a DC voltmeter.

Check the state of charge with Table 1 below.

Charge the battery if it registers 0% to 70% charged.

[Tony Lee]

Perhaps when you disconnect shore power or generator, AC load that was being supplied is suddendly switched over to the inverter so if it was a reasonable load, that might cause a sudden dip in the battery voltage that is sustained long enough to trigger the auto start sequence.

[vsheetz]

Originally Posted by Pogo

The voltage reading on a nearly discharged battery could read the same as on a fully charged one, until a load is applied.

This does not align with my experience. SoC tables such as I shared above are typically for a battery at rest. With load the voltage will be reduced.

[georgeaz]

I ordered a Schumacher BT-100 load tester for $20 bucks on Amazon.

https://www.amazon.com/gp/product/B000AMBOI0/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I will give it shot.

I would rather not disconnect the battery, just to try to get a read on it. I am always leery of things needing to be reset when power is removed. Will that work if the coach is unplugged and everything is turned off? I realize there might be some micro drains, but as I said, I am just trying to see if there really is a problem.

Thanks,

G

[Pogo]

The voltage reading on a nearly discharged battery could read the same as on a fully charged one, until a load is applied. Then you can tell the difference.

This above information was taken directly from my Holiday Rambler/Monaco owners book manual in the chapter on batteries. They have a long explanation on why this is correct. You may see the same thing in your manual.
Apparently, the RV manufacturer has published incorrect information. And, I didn't know that they didn't know better. Thanks for telling me. I was only trying to help.
I stand corrected. Thanks

[rewillia]

Within 5 mins of shore power disconnect
13.0 v >>> 11a invert